This patch allows multiple iovecs as argument in spdk_dif_generate_stream. Subsequent patches will support DIF strip and insert in SPDK NVMe-TCP target based on the patch series. Change-Id: I1f3d6c5b9f924bb52525e1611db403846d087563 Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com> Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/453756 Tested-by: SPDK CI Jenkins <sys_sgci@intel.com> Reviewed-by: Changpeng Liu <changpeng.liu@intel.com> Reviewed-by: Jim Harris <james.r.harris@intel.com>